Provided is an integrated circuit device including a source line extending in a first horizontal direction on a substrate, a channel layer extending in a vertical direction, disposed on the source line, and having a first sidewall and a second sidewall, a trapping layer on the first sidewall of the channel layer and including an oxide semiconductor, a word line on at least one sidewall of the trapping layer and extending in a second horizontal direction crossing the first horizontal direction, a gate insulation layer between the at least one sidewall of the trapping layer and the word line, and a bit line electrically connected to the channel layer and extending in the first horizontal direction, wherein the channel layer has a first bandgap energy, and the trapping layer has a second bandgap energy that is greater than the first bandgap energy.